Pentasil Catalyst Propylene Yield FCC Process
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Solution Overview
Problem
Current fluidized catalytic cracking (FCC) processes face limitations in maximizing light olefin production, particularly propylene, while maintaining gasoline yields, due to the restricted capacity of wet gas compressors and the deactivating effects of coke deposition on catalysts.
Innovation Solution
A fluidizable catalyst composition comprising pentasil zeolite with 10-24% phosphorus and 1-10% iron oxide outside the zeolite framework, combined with additional zeolites like Y zeolite, enhances olefin yields and maintains gasoline production by stabilizing the catalyst and improving attrition resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ZSM-5-based additive catalyst is used to enhance light olefin yields, then propylene production increases, but the capacity is restricted by the wet gas compressor and LPG production limits
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating iron oxide (1-10% by weight) in addition to phosphorus (10-24% by weight) on pentasil zeolite. This compositional modification alters the catalytic properties to enhance propylene selectivity and yield per unit of LPG, thereby increasing propylene production without being constrained by compressor capacity limits.
2Productivity
If severe cracking conditions are applied to overcrack feed to small olefins, then light olefin yields increase, but coke production increases and catalyst deactivates faster
Solution Approach 1:
The patent modifies the catalyst composition parameters by adding iron oxide to the phosphorus-pentasil system, creating a catalyst that maintains high activity under severe cracking conditions. This compositional change enables the catalyst to resist deactivation from coke deposition, allowing sustained operation at high temperatures and high catalyst-to-oil ratios that maximize light olefin production.
Solution Approach 2:
The patent creates a composite catalyst material combining pentasil zeolite, phosphorus, and iron oxide. This composite structure synergistically enhances the catalyst's resistance to coke deactivation while maintaining high cracking activity, enabling severe operating conditions to be applied without the negative effects of rapid catalyst deactivation.
3Quantity of substance
If Y zeolite is used in conventional FCC processes, then gasoline yield is maintained, but olefin saturation increases and light olefin production decreases
Solution Approach 1:
The patent applies local quality by using pentasil zeolite with iron oxide and phosphorus specifically for olefin production functions, while Y zeolite handles the gasoline production function. The iron oxide-modified pentasil provides localized high olefin selectivity without the hydrogen transfer properties of Y zeolite that would otherwise saturate olefins, enabling simultaneous optimization of both gasoline and olefin yields.
4Productivity
If conventional catalyst is reduced to minimize olefin saturation, then light olefin selectivity improves, but gasoline yield decreases
Solution Approach 1:
The patent creates a composite catalyst system where iron oxide-modified pentasil zeolite and Y zeolite work together. The pentasil component with iron oxide and phosphorus provides high olefin selectivity, while the Y zeolite maintains gasoline production capability. This composite approach eliminates the need to sacrifice gasoline yield when optimizing for olefin selectivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst composition significantly increases propylene selectivity per unit of LPG, allowing for higher propylene production without significant capital expenditure or severe operating conditions, and maintains catalyst activity and attrition resistance.
Implementation Method 1
A fluidizable catalyst composition comprising pentasil zeolite having a silica/alumina framework, 10 to 24 percent by weight phosphorus, measured as P2O5, 1 to 10 percent by weight iron, measured as Fe2O3, present outside the pentasil framework
Implementation Method 2
use of catalysts to enhance yields of light olefins and liquefied petroleum gas (LPG) produced in a fluidized catalytic cracking (FCC) process
Data Source
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AI summary
The catalyst of this invention is capable of enhancing light olefin, e.g., propylene, yields in fluidizable catalytic cracking (FCC) processes. The catalyst comprises (a) pentasil zeolite, (b) at least 5% by weight phosphorus (P2O5) based on particles containing the pentasil, and at least about 1% by weight iron oxide, as measured by Fe2O3, outside of the pentasil zeolite's framework. The catalyst is fluidizable and has an average particle size in the range of about 20 to about 200 microns. The catalyst composition can further comprise additional zeolite suitable for cracking hydrocarbons in a FCC process. The catalyst has been shown to be highly active compared to other catalysts and shows a high selectivity for propylene produced in an FCC process.